Brake mechanism for tiltable propeller units



Dec. 17, 1968 K. A. BERGSTEDT BRAKE MECHANISM FOR TILTABLE PROPELLERUNITS 3 Sheets-Sheet 1 Filed Dec. 19, 1966 I mvsmon KARL ABm/v Bmesrwryii ywk ATTORNEY 17, 1963 K. A. BERGSTEDT 3,416,483

BRAKE MECHANISM FOR TILTABLE PROPELLER UNITS Filed Dec. 19, 1966 v 5Sheets-Sheet 2 INVENTOR hA RL ABDONBERGSTEDT Dec. 17, 1968 K. A.BERGSTEDT 3,416,483

, BRAKE MECHANISM FOR TILTABLE PROPELLER UNITS Filed Dec. 19, 1966 3Sheets-Sheet 3 FIG. 3

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United States Patent 3,416,483 BRAKE MECHANISM FOR TILTABLE PROPELLERUNITS Karl Abdon Bergstedt, Goteborg, Sweden, assignor to AB Penta,Goteborg, Sweden Filed Dec. 19, 1966, Ser. No. 602,820 Claims priority,application Sweden, Dec. 22, 1965, 16,680/ 65 7 Claims. (Cl. 115-41) Aboat drive arrangement including a tilting outboard power leg and havinga brake comprising a drum and friction band, the drum being coaxial withthe tilt axis of the outboard power leg and the brake restrainingtilting movement of the leg.

In those drive arrangements for boats which consist of an outboard powerleg or propeller unit mounted in the stern of the boat and which may becoupled to an inboard engine, for example, the outboard unit ispreferably tiltable so as not to be damaged in case of running aground.In normal forward operation, the propeller thrust keeps the unit inoperating position, so that it may be freely pivoted, but it mustnevertheless be retained in this position with enough force so that thepropeller housing when throttling down in motion will not be shifted upbecause of the resistance of the water. If in that case the motor isaccelerated again before the boat has stopped, the partly tiltedpropeller unit will strike against the abutment on the boat with greatforce, which may cause damage. The same may occur whenever the outboardleg re- Q turns from the fully or partially tilted position,particularly when power is 'being applied to the propeller for forwarddrive. In reverse operation, it is necessary to lock the pivotingmotion, as the propeller thrust will tend to swing the unit upward.

It has been known to lock the outboard leg of a boat drive with a hookor the like to secure the leg positively against tilting for reverseoperation but with less effort in forward operation such that therestraint of the hook or latch is overcome when the leg strikes anunderwater object. This locking device has the disadvantage that as soonas the hook is released, the propeller unit can swing freely and may bedamaged either when abruptly stopped as it reaches its maximum tiltposition or when it swings back into operating position under the thrustof the propeller.

The present invention relates to an arrangement by means of which boththe upward and the downward tilt can be braked at will, while at thesame time the leg may be effectively locked in normal operating positionwhile driving the boat in reverse, i.e. while backing down, and may alsobe restrained or locked in any intermediate partially tilted position.The characteristic feature of the invention is a brake drum arrangedcoaxially with the tilt pivot of the outboard leg to cooperate with abrake band of which the reaction is transmitted to a part fixed withrespect to the boat.

The novel features which are believed to be characteristic of thisinvention are set forth with particularity in the appended claims. Theinvention itself, however, both as to its organization and method ofoperation, together with further objects and advantages thereof, maybest be understood by reference to the following description taken inconnection with the accompanying drawing, in which:

FIG. 1 shows a side view of the stern of the boat with aninboard-outboard power leg (a propeller unit) provided with a brakemechanism according to the invention,

FIG. 2 shows a lengthwise section of a transmission case belonging tothe propeller unit in FIG. 1,

FIG. 3 is a fragmentary sectional view taken generally ice along line 33of FIG. 1 on an enlarged scale showing details of portions of the brakemechanism, and

FIG. 4 is a fragmentary side view on an enlarged scale of a portion ofthe mechanism as seen in FIG. 1 with parts in position corresponding tooperation of the drive in reverse gear.

In the stern transom 1 of boat 40 there is an opening 2 covered by ashield 3. The shield 3 carries bearings 4 disposed forwardly of theshield, that is, within the boat and these hearings mount a transmissioncase 5 freely rotatable on an axis of rotation which is horizontal andparallel to the stern transom 1. The shield 3 is provided with anopening 30 for an intermediate shaft 6 for driving a propeller. Theshaft 6 is enclosed in the outboard housing or leg 7 which mounts thepropeller, as shown, for example, in my application entitled DriveArrangement for Motor Boats, filed Nov. 29, 1966, Ser. No. 597,769. Theintermediate propeller drive shaft 6 is supported for rotation in thetransmission case 5, and as the propeller housing or outboard leg swingsin a vertical plane, i.e. when it tilts on the aforesaid axis, thetransmission case rotates on its bearings 4. At one end of thetransmission case, an input shaft 8 is mounted in bearings 31 in suchmanner as to be coaxial with the geometrical axis of rotation of thetransmission case 5, and the shaft 8 is connected by a belt sheave 9 orthe like to a motor, not shown, set up in the boat. The shaft 8 isconnected in known manner by double bevel gears to the intermediateshaft 5 for forward and reverse operation, for example, as shOWn in myUS. Patent No. 3,269,497. At the opposite end of the transmission case 5there is an operating means 10 for the clutch 32 of the transmission andon the end 33 of the transmission case is a cylindrical braking surfaceor drum 11. The axis of rotation of surface 11 is concentric with thegeometrical axis of the transmission case 5. The brake drum 11 isencircled by a double-action friction brake band 12, controlled by astop member in the form of pin 13 fixed with respect to the boat byattachment to shield 3 by means of socket member 41 and nut 42 boththreadedly engaged on the pin.

The brake band is provided at its end with lugs 14 and 15 having holes34 and 35 through which pin 13 extends. The holes a-re large enough topermit pin 13 to slide freely therein. On either side of the lugs 14,15, the pin 13 has fixed stop lands 16, 17. Outside or beyond the stops,the pin 13 is threaded and fitted with nuts 18, 19, and between each nutand the adjacent lug of the brake band 12, a coil spring 20, 21 isinserted. The spring compression of each spring can be regulated bydrawing up or tightening the respective nut 18 or 19, thereby toincrease the bias against the respective lug. It will be seen that lands16 and 17 are arranged outwardly of the lugs, that is, not between thelugs, and that land 16 is disposed behind lugs 14, and land 17 behindlug 15.

The brake mechanism functions as follows. The nuts 18 and 19 aretightened enough so that the brake band 12 acts with some friction onthe brake drum 11. If outboard leg 7 swings up or tilts for any reason,the lug 15 is pressed by the force transmitted through the hand againstthe stop land 17, while the lug 14 is acted upon by the spring 20 in thesame direction. The result is a servo or self-applying brake effectwhose force depends on the adjusted spring tension of spring 20. Whenthe propeller housing is lowered, the brake band 12 will turn in theopposite direction, holding leg 14 against the stop land 16, while leg15, under the action of spring 21 and the friction between the brakedrum 11 and the brake band, is shifted to the left in FIG. 1, providinga brake action on the downward swing which is adjustable at will. Theadjustment of spring 21 should be sufiiciently tight to prevent anexcessive blow against the shock absorbent abutment means 36 when theleg returns to operating position but the adjustment for normaloperation should be not so tight as to prevent return of the leg fromits tilted position. If the nut 19 is tightened to compress spring 21sufficiently to cause lug 14 to engage or nearly engage stop 16, thebraking action upon the return of the leg from tilted position will besubstantially increased, and it will be increased to a greater extentthan the braking force resisting tilting, whereas tightening of nut 18to further compress spring 20, will increase resistance to tilting to agreater extent than it increases resistance to the return movement ofthe leg. If either or both of nuts 18 and 19 is tightened, the band maybe caused to grip the drum sufiiciently tightly to retain the leg inoperation position while backing down, though if one wishes to utilizesuch adjustments to prevent tilting of the leg during reverse driving ofthe propeller, less tightening of nut 18 would be required to providesufi'icient braking action than would be the case, if nut 19 istightened. Tightening of one or the other or both of nuts 18 and 19 willpermit locking of the leg in any desired angle of tilt, such as foroperation in shallow water. If spring 20 were omitted or madeineffective by backing ofi nut 18, the band would have little brakingeffect as the leg tilts but, under the influence of spring 21, thereturn movement of the leg from tilted position would be substantiallyretarded or braked.

For reverse operation, the brake action obtained by tightening nut 18 tocompress spring 20, or tightening of both nuts, may be insufficient toretain the outboard leg 7 in operating position, and for this reason amore positive locking means is preferably associated with the brakemechanism, which locking means in the illustrated embodiment is coupledfor operation by the control linkage for the reverse gear so that bothare actuated simultaneously.

This linkage included in the reverse gear control consists of arotatable shaft or rod 10 entering into the transmission case 5 throughan opening 39 in the center of the brake drum 11, i.e. along the axis ofrotation of the transmission case, rotation of the shaft being effectedby a lever 23 fixed to the end thereof and connected by links 24, 25 toa remote control bar 26. A rod 27 or the like is articulated to lever 23and is guided for movement in a direction substantially radially of thebrake drum 11 by a guide 38 fixed to the brake drum, and, thus, to thetiltable leg structure. When the lever arm 23 is swung into the positionwhich it assumes upon shifting into reverse gear, as shown in FIG. 4,the end portion 37 of the rod 27 projects outwardly alongside of thebrake band 12. As best seen in FIG. 3, alongside of lug 14 andpreferably forming a part of the lug, there is a laterally projectingpost or knob 28, carrying a setscrew 29. The end portion 37 of the rod27 can cooperate with knob 28 which is fixed to lug 14 throughengagement with setscrew 29. When the gear is placed in reverse byraising clutch member 32, which is accomplished by moving control rod 26to the left as seen in FIG. 2, the rod end 27 is caused to project fromthe brake drum, as best seen in FIG. 4, and then, when the leg hastilted through a few degrees from normal operating position as a resultof the reverse propeller thrust, and when transmission case 5 hasrotated therewith slightly in the clockwise direction as seen in FIG. 1,the rod end portion 37 will engage the end of setscrew 29 and move theknob 28 and lug 14 in a direction to tighten the brake band on the drum,thus to arrest the tilting motion of the leg. Setscrew 29 permitsadjustment of the number of degrees through which the transmission casewill rotate, in the direction of increasing tilt of the leg, in whichdirection the transmission case tends to rotate when the boat is beingdriven in reverse, before the brake band tightens on the drum.

While the brake mechanism described above is especially suitable forthose boat drives which comprise a tiltable 1. In a boat propulsionarrangement including an outboard power leg tiltably mounted on a boatby means establishing a horizontal tilt axis for said leg, thecombination of a brake drum fixed to said leg coaxial with said tiltaxis, a friction brake band having opposite ends, a respective lugafiixed to each said end, said band being disposed around said drum withsaid lugs in proximity, means for urging said lugs toward each otherthereby to engage said band with said drum, and for restraining saidhand against rotating with said drum, said last means comprising a fixedstop member having a respective stop land for each said lug disposedbehind its respective lug and each land being selectively engageable byits respective lug when said leg tends to move on said axis, said lastmeans further comprising a respective spring for each lug, means fixinga first portion of each said spring with respect to said stop member,each said spring having a second portion engaging and urging itsrespective said lug in a direction toward the other said lug and awayfrom its respective stop land.

2. The combination according to claim 1 wherein the means fixing thefirst portion of at least one of said springs with respect to said stopmember comprises an element adjustably attached to said stop member foradjusting the force exerted by such spring against its respective saidlug.

3. The combination according to claim 1 wherein said leg is providedwith retractable and extendable forceapplying means disposed, whenextended, in a position to impose brake-band-tightening force upon oneof said lugs in response to predetermined tilting movement of said legon said axis and when retracted to be inoperative to impose such force,and wherein means are provided for selectively extending and retractingsaid force-applying means.

4. The combination according to claim 3 wherein said leg comprises atransmission case at its upper end which is rotatable on said axis, aforward and reverse transmission in said case, a forward-reverse controlelement entering said case for controlling the transmission, whereinsaid retractable and extensible force-applying means is positioned uponextension thereof and upon slight tilting of said leg from its operatingposition, said brake-bandtightening force to that one of said lugs whichincreases the frictional engagement of said band upon such tilting ofthe leg, and wherein said extending and retracting means for saidforce-applying means is coupled to said control element for extendingsaid force applying means in response to operation of said control meansin a direction to place said transmission in reverse.

5. The combination according to claim 2 wherein said stop membercomprises a post, said lugs being provided with openings through whichsaid post freely extends, wherein said means fixing the first portion ofat least said one of said springs comprises a nut, and said post isprovided with threads engaged with the threads of said nut.

6. In a boat propulsion arrangement including an outboard power legtiltably mounted on a boat by means establishing a horizontal tilt axisfor said leg, the combination of a brake drum fixed to said leg coaxialwith said tilt axis and rotatable in a predetermined direction withtilting of said leg, a friction brake band having opposite ends, a lugaffixed to one said end, said band extending from its said one endaround said drum in said predetermined direction and having its saidends in proximity, fixed means retaining said other end of said bandagainst movement in a direction opposite to said predetermineddirection, and spring means having one portion fixed with respect tosaid fixed means and another portion engaging said lug urging said 111gtoward said opposite direction and toward said other end of the band,whereby said band frictionally retards the return movement of said legfrom tilted toward normal operating position. 4

7. The combination according to claim 6 wherein said means retainingsaid other end of said band includes a stop portion engageable by saidother end when said band is frictionally urged by rotation of said drumin said opposite direction and further includes a spring urging saidother end in said predetermined direction and away from said stopportion, and wherein fixed stop means are provided in a position to beengaged by and limit the movement of said lug in said predetermineddirection against the force of said spring means.

References Cited UNITED STATES PATENTS 1,729,015 9/1929 Seidman.2,304,646 12/1942 Lear 188-77 X DUANE A. REGER, Primary Examiner.

US. Cl. X.R. 18877, 166

1. IN A BOAT PROPULSION ARRANGEMENT INCLUDING AN OUTBOARD POWER LEGTILTABLY MOUNTED ON A BOAT BY MEANS ESTABLISHING A HORIZONTAL TILT AXISFOR SAID LEG, THE COMBINATION OF A BRAKE DRUM FIXED TO SAID LEG COAXIALWITH SAID TILT AXIS, A FRICTION BRAKE BAND HAVING OPPOSITE ENDS, ARESPECTIVE LUG AFFIXED TO EACH SAID END, SAID BAND BEING DISPOSED AROUNDSAID DRUM WITH SAID LUGS IN PROXIMITY, MEANS FOR URGING SAID LUGS TOWARDEACH OTHER THEREBY TO ENGAGE SAID BAND WITH SAID DRUM, AND FORRESTRAINING SAID BAND AGAINST ROTATING WITH SAID DRUM, SAID LAST MEANSCOMPRISING A FIXED STOP MEMBER HAVING A RESPECTIVE STOP LAND FOR EACHSAID LUG DISPOSED BEHIND ITS RESPECTIVE LUG AND EACH LAND BEINGSELECTIVELY ENGAGEABLE BY ITS RESPECTIVE LUG WHEN SAID LEG TENDS TO MOVEON SAID AXIS, SAID LAST MEANS FURTHER COMPRISING A RESPECTIVE SPRING FOREACH LUG, MEANS FIXING A FIRST PORTION OF EACH SAID SPRING WITH RESPECTTO SAID STOP MEMBER, EACH SAID SPRING HAVING A SECOND PORTION ENGAGINGAND URGING ITS RESPECTIVE SAID LUG IN A DIRECTION TOWARD THE OTHER SAIDLUG AND AWAY FROM ITS RESPECTIVE STOP LAND.